Rapid and continuous expansion of electronic devices, with an emphasis on wireless and handheld technology, has placed new challenges on semiconductor manufacturing. Device technologies have evolved, demanding smaller transistors with greater performance. Improving device performance and lowering deleterious leakage currents in devices has become an important area of focus. One semiconductor manufacturing process that plays a contributory role in deleterious leakage currents in formed devices is ion implantation processing.
Ion implantation introduces damage in a lattice structure of a semiconductor workpiece (e.g., silicon) based on many factors, including dosage of ions being implanted, a mass of the implanted ion, a dosage rate (ions/cm2/second), and workpiece temperature. Ion implantation processing typically produces point defects in the workpiece, wherein interstitials, vacancies, and other point defects occur during implantation. Conventionally, point defects subsequently form extended defects upon annealing of workpiece, wherein the point defect can extend into active areas of the workpiece. The extended defects, for example, can cause junction leakage in the formed device, such as leakage from a source/drain region to a well region of the device. Ultimately, these leakages have the potential to increase the power required to operate the device and/or increase standby power consumption of the device.
One factor in determining the average dose rate of the ion implantation process is the architecture of the ion implanter. For example, in a batch or multi-workpiece system, a plurality of workpieces are concurrently implanted with ions, often by spinning a platen on which the plurality of workpieces rest through a stationary ion beam or ribbon beam. In a single-workpiece system, a single workpiece is individually scanned in one dimension or two dimensions with respect to an ion beam which may also be scanned. The architecture of the ion implantation system can have a profound effect on the average dose rate for any particular location on the workpiece, and thus, the degree of damage caused in a lattice structure of the workpiece. For example, a single-workpiece system has a higher effective dose rate than a batch system, despite both systems having common ion beam densities, thus making single-workpiece ion implantation systems desirable for devices requiring high-dosage implants where it is desired to maximize the damage to the lattice structure of the workpiece.
For example, among single-workpiece architectures, different scanning methodologies have been employed in commercial ion implantation systems, with a variation in one-dimension mechanical scanning combined with electrostatic and/or magnetic scanning for horizontal spread of the ion beam and increased uniformity. These systems have focused on high throughput and minimum cross-wafer dose variation as key attributes affecting design implementations. However, damage to the lattice structure of the workpiece caused by either high-dosage and/or high energy implants in single-workpiece architectures has been problematic. Therefore, a need exists in the art for an apparatus, system, and method for controlling localized damage accumulation on a workpiece while optimizing workpiece throughput in a single-workpiece ion implantation architecture.